Manufactured by Amazon.com discs:There had been some discussion in the recent purchases thread about these discs and having received one as a gift, several posters asked me to help elaborate so we could figure out the ins and outs of this thing, so I'll attempt to show what I can here. This deals with CDs ordered from Amazon with this caveat: "CD-R Note: This product is manufactured on demand when ordered from Amazon.com. [Learn more]"

There was a question over whether or not the files were sourced by mp3s or by uncompressed audio, and some users requested I take screen shots of the waveform. They are below. Amazon.com's claim: "CreateSpace works with many of the leading music labels, television networks, film studios, and other distributors to make these titles available to Amazon.com customers. All products are manufactured from original source materials (e.g., for audio products, uncompressed CD-quality audio)."

wav file ripped directly from my shitty arse vengeance rising cd bootleg, whoever made the thing used mp3s or some other such lossy formatnotice how the frequencies above 20 k aren't there?

Don't know the album but this may be normal (maybe the production is on the dark side), also there's not an abrupt drop on the frequency so it doesn't seem anything out of the ordinary there.

dreadmeat wrote:

and this dark angel leave scars vinyl rip

...farkin heinous!

Not a fair comparison, the CD format only has frequencies up to 22 kHz while vinyl can go up to 45 kHz. Both are good as freqs > 22 kHz aren't heard unless you're, for instance, a dog, or a cat (well, even vinyl is lacking for cats as they cancat detect sound all the way up to 64 kHz, and they are pretty damn cute on top of that).

re plot spectrum you have two different results because the 'sample size' used was different for each one, 512 and 128the smaller the sample size the more accurate it'll be [and it'll take longer] i found using a part of the song with a lot of sound eg not the intro gave a better result, i'm not sure why they have it limited to that length, i had a few different limits presented to me about 1 to 2 minutes roughly [their wiki/faq etc likely has the answer]

my first question is: did you rip the cd to wav or mp3? if you ripped to wav then i think amazon have some *explaining to do, as above there's nothing over 20k?my vengeance rising cd up there is a bootleg so the jammy fucker probably just used mp3s to burn the disc

"CreateSpace works with many of the leading music labels, television networks, film studios, and other distributors to make these titles available to Amazon.com customers. All products are manufactured from original source materials (e.g., for audio products, *uncompressed CD-quality audio)."

addendum, oh look, japc replied at the same timei agree, cats are cute, but those baby goat videos take some beating

also i chose the vinyl rip to show the very different results, i'm keen to try a new record with more modern productionand maybe some drum n bass vinyl too, something 100% electronic, just for the fun of it.

Not a fair comparison, the CD format only has frequencies up to 22 kHz while vinyl can go up to 45 kHz. Both are good as freqs > 22 kHz aren't heard unless you're, for instance, a dog, or a cat (well, even vinyl is lacking for cats as they cancat detect sound all the way up to 64 kHz, and they are pretty damn cute on top of that).

Actually, CD audio has a sampling rate of 16bit/44Khz, what vinyl has better is a wider dynamic range. Also there's another factor that is the actual bit rate of the MP3 to CD audio conversion, since MP3 has a sampling rate identical to an audio CD. What happens, and is partially explained in that linked article, is that at lower bit rates the codec that compresses the file cuts all frequencies above a certain threshold to save physical space. MP3 at 320Kbps is capable of reproducing the audio perfectly, although the fact that it's a lossy format will make some things be lost as well, although those are the ones which can only be "felt" or heard with really high-end gear, i.e. nothing that would really make that much of a difference. But I don't even want to go down that road because this would rapidly turn into a lossy vs lossless debate.

What's important to realize is that if a CD is recorded from a low bit rate MP3 source it will wave a waveform with the higher frequencies completely cut out.

Actually, CD audio has a sampling rate of 16bit/44Khz, what vinyl has better is a wider dynamic range.

That's the sampling rate, the Nyquist frequency is half that: 22 kHz.

androdion wrote:

Also there's another factor that is the actual bit rate of the MP3 to CD audio conversion, since MP3 has a sampling rate identical to an audio CD. What happens, and is partially explained in that linked article, is that at lower bit rates the codec that compresses the file cuts all frequencies above a certain threshold to save physical space. MP3 at 320Kbps is capable of reproducing the audio perfectly, although the fact that it's a lossy format will make some things be lost as well, although those are the ones which can only be "felt" or heard with really high-end gear,

For me everything over 192 I can't distinguish from the CD, it was too many years using lowsy chinese shop headphones (soft version of sticking a driller in the ear drum). Which is pretty cool as I can fit more music on the portable player, or rather "would be", because I tend to encode everything with -V0 (320/vbr) anyway with fear of missing something.

hmm i was convinced i understood the data i was looking at but i may be a shade foggy still...i ripped some crappy bootleg cd-r and a couple of legit cd-rs and some mastered [silvered] discs and the results are all the same: 20k as abovethe only results that looked a lot different were the vinyl rips

Actually, CD audio has a sampling rate of 16bit/44Khz, what vinyl has better is a wider dynamic range.

That's the sampling rate, the Nyquist frequency is half that: 22 kHz.

I tried reading the Wiki article about the Nyquist frequency but it's like reading Chinese!

So in real life all actual audio is only reproduced within the borders of the Nyquist frequency, i.e. half of the original sampling rate? And is that why the graph only shows a curve up until the upper 20Khz?

dreadmeat wrote:

the only results that looked a lot different were the vinyl rips

Reading the last linked article that actually makes sense and comes in line with what I've said before, only low bit rate MP3 sources give out crappy CD-R copies.

I still find it weird that a company would have copyright access to (supposedly) lossless source files of the albums sold by a label. It's a brave new world we're living in!

So in real life all actual audio is only reproduced within the borders of the Nyquist frequency, i.e. half of the original sampling rate? And is that why the graph only shows a curve up until the upper 20Khz?

so if i'm reading this correctly there appears to be no way to tell if a cd has been burned from mp3 files or wav files or flac or indeed even mastered [made from the original master, i'm unsure of the actual terminology]because they all appear to look very similarthe only way it'll look any different is if it was ripped from vinyl or burned from really crappy files, right?

that's burst my bubble a wee bit, i was hoping there was a way to tell

so if i wanted to make some bootleg cds all i'd have to do rip the vinyl, burn those files to the cd and claim they have "much higher bitrates than mp3s [or some other such nonsense] hence they have to be legit"i bet the scumbag bootleggers already know about this

It would be much easier to have one original copy of each rare CD and make a lossless copy of it, then you can reproduce the entire audio tracks seamlessly. No one would be able to tell the difference. And yes, according to the graphs and articles linked before you can tell if the source files were low bit rate MP3 files because of the cut-off threshold. Now if the copy is made from high bit rate MP3 or lossless files it's nearly impossible to discern I guess.

Bootlegging is actually pretty easy to do, and given the right amount of knowledge one can do near perfect bootlegs. And my fear is that it will only get worse as these items become rarer and increase in value. If those Amazon CD-Rs are indicative of anything is that a new facet of the CD market is now emerging, one where people only care about having the actual audio in physical format without having to pay loads of money. If this tendency grows one day you'll stop having labels producing actual CDs and booklets, and relinquishing that responsibility towards large distributors/retailers. I dread the day that becomes an actual possibility.

It would be much easier to have one original copy of each rare CD and make a lossless copy of it, then you can reproduce the entire audio tracks seamlessly. No one would be able to tell the difference. And yes, according to the graphs and articles linked before you can tell if the source files were low bit rate MP3 files because of the cut-off threshold. Now if the copy is made from high bit rate MP3 or lossless files it's nearly impossible to discern I guess.

If you use lossless you shouldn't be able to discern as they're bit equal to the wav/cdda. As for mp3 high bit rates tend to get pretty close but that depends on the encoder, you should be able to find something fishy most of the time.

This brings to mind an app I found some time ago when I was very into this stuff, it's called http://www.sonicvisualiser.org and gives plenty of ways to look at sound (I haven't explored a tiny fraction of it). To showcase the application and the wav/flac vs mp3 here's 3 spectrum screenshots (with the default colour scheme) of Carnivore's Race War:

The wav versions goes smoothly loosing intensity until 22 kHz, the others have artificial cutouts lower than that. But hen again they can have the cutouts and be sourced from the CD (dunno, weird filtering on the studio on something like that) or don't have the cutouts because the mp3 encoder is really amazing. Anyway, Sonic Visualizer is pretty cool.

If you use lossless you shouldn't be able to discern as they're bit equal to the wav/cdda. As for mp3 high bit rates tend to get pretty close but that depends on the encoder, you should be able to find something fishy most of the time.

Actually that works for tracks but to make an exact CD copy you need a bit more than each of the CD tracks in lossless (you'll need the pre-track gap data, for instance).

If you use lossless you shouldn't be able to discern as they're bit equal to the wav/cdda. As for mp3 high bit rates tend to get pretty close but that depends on the encoder, you should be able to find something fishy most of the time.

Actually that works for tracks but to make an exact CD copy you need a bit more than each of the CD tracks in lossless (you'll need the pre-track gap data, for instance).

True.

Those graphs above are very interesting indeed. It would be interesting to use that program to see if older albums which are lesser compressed than more recent ones have differences above the 20Khz mark. Basically to see if loudness war actively killed everything above 20Khz on modern productions.

Those graphs above are very interesting indeed. It would be interesting to use that program to see if older albums which are lesser compressed than more recent ones have differences above the 20Khz mark. Basically to see if loudness war actively killed everything above 20Khz on modern productions.

I don't think so, if anything, the color intensity would be brighter across the whole frenquency range, up to 22 Khz.

I don't think so, if anything, the color intensity would be brighter across the whole frenquency range, up to 22 Khz.

That should never happen, most things happen on the bass, mid and high ranges, little more than cymbals and hit-hats go on the higher frequencies. So the graphic should always be brighter on the bass/mid/high. Check http://obiaudio.com/2010/07/11/eq-chart/

I don't think so, if anything, the color intensity would be brighter across the whole frenquency range, up to 22 Khz.

That should never happen, most things happen on the bass, mid and high ranges, little more than cymbals and hit-hats go on the higher frequencies. So the graphic should always be brighter on the bass/mid/high. Check http://obiaudio.com/2010/07/11/eq-chart/

Yes, but since the loudness of the whole signal is being boosted, the higher frequencies (if present) would also be louder (have a higher amplitude than before), resulting in a brighter color in a spectrogram. Relative to lower frequencies, of course, they will always be less intense, i.e. that upper frequency region on the specrogram will be less bright.What i wanted to say, though, is that i think it's unlikely that modern Loudness War productions would remove any content above 20 KHz.

Edited for clarity (hopefully )

Last edited by Flaisch on Sun Dec 30, 2012 2:37 pm, edited 1 time in total.

Yes, but since the loudness of the whole signal is being boosted, the higher frequencies will also be louder, resulting in a brighter color in a spectrogram. Relative to lower frequencies, of course, they will always be less intense.What i wanted to say, though, is that i think it's unlikely that modern Loudness War productions would remove any content above 20 KHz.

Yes, you're right, I don't also think there should be anything relevant (cutouts for instance) on the spectogram.

But the worse I've seen is Behexen - From the Devil's Chalice, not a remaster but a case study so bear with me. I bought it yesterday from SoM sale for 3€, and upon reading some reviews what most people mentioned, besides the great music, was the lowsy mastering. I think someone made a rookie mistake somewhere as that isn't normal (just listen to it).

Track 01 - Invocation Of Zabulus, just look at how the righ channel (low graph) is completely flat at most of the time:

whoah, yeah that's really bad.death magnetic looks similar [but not quite as much clipping] i bet defiled's in crisis album would also look interesting...it's not so bad if the music is 'fuzzy' already, lots of distortion, death/black metal screams etc but anything clean sounds appalling, or at least more noticeable

it pisses me off when i change cds and have to reach for the volume control lest i blow a hole in the wallwhen i listened to mp3s a lot more i ran mp3gain on them but the only way i can avoid it with cds is to play them in the pc and use normalisation [which i don't want to have to do]

so if i'm reading this correctly there appears to be no way to tell if a cd has been burned from mp3 files or wav files or flac or indeed even mastered [made from the original master, i'm unsure of the actual terminology]because they all appear to look very similarthe only way it'll look any different is if it was ripped from vinyl or burned from really crappy files, right?

that's burst my bubble a wee bit, i was hoping there was a way to tell

so if i wanted to make some bootleg cds all i'd have to do rip the vinyl, burn those files to the cd and claim they have "much higher bitrates than mp3s [or some other such nonsense] hence they have to be legit"i bet the scumbag bootleggers already know about this

I use foobar2000 with the Dynamic range meter component, when you view the log files it tells you what the bit rate is. Here is one I did of Boris- Akuma no uta, intentionally ripped to my computer with lower then cd quality.

Anyone has the Omen - Battle Cry reissue from Metal Blade with the black backcover with the large Omen Battle Cry?

Just got a copy from an amazon 3rd party (http://www.amazon.co.uk/gp/product/B000 ... 02_s00_i00) very cheap, and some things strike me as odd: it was sealed but one of the spines is torn, it has no inner print on the backcover but comes in a transparent jewelcase, the backcover layout is very much like the limited edition (black with the large band + title) but without the limited edition on the bottom right, the cover is very blurry and the paper feels weird.